Focus Fanatics Forum banner

How-To: SVT LSD Differential Install

62K views 71 replies 28 participants last post by  Mile30  
#1 · (Edited)
I can take no credit in writing this how-to. It was downloaded elsewhere and i am now presenting it for all FocusFanatic.com members.

Installation instructions for Quaife ATB differential in Getrag MT 285 Transaxle

Parts you will need:
Differential carrier bearings (2 sets) NAPA part # BR35 or SKF #LM501310 and LM501349 (you will need 2 of each).

The output shaft oil seals (one of each) 36mmX58mmX11mm and 40mmX62mmX11
Ford part numbers: 2M5V-3K169-AA and 2M5V-3K169-BA

The input shaft oil seal is only available as part of the Throw out bearing assembly so if you don't want to buy one be very careful when removing and installing the bell housing section over the input shaft. Ford part number for Seal with housing 2M5V-7A564-AA

Instructions:
Drain oil from gearbox and remove from car per factory service procedure.

Remove lower torque arm bracket from gearbox.

Remove 19 torx head bolts holding gearbox case together (make sure you get them all, a couple of them are hidden in the ribs on the case) , some are inside the bell housing and some are outside the gearbox. With a suitable punch drive the 2 locating pins from the case; be careful not to damage the case by running the punch into the case.
Image

With the bell housing facing up use a soft hammer (dead blow) to brake the case half's apart (there is a sealant holding it together) DO NOT USE A SCREWDRIVER TO PRY IT APART YOU WILL DAMAGE THE MACHINED SURFACE AND IT WILL NOT SEAL WHEN YOU PUT IT BACK TOGETHER.

Lift the bell housing off the input shaft being careful not to damage the input shaft seal. All of the gears will remain in the lower case half.
Image



The differential carrier with crown wheel can now be lifted out of the case.

Image

Remove the 10 bolts holding the crown wheel to the carrier. Using a soft hammer or wood block work the crown wheel off the carrier by tapping around the outer edge (it is lightly pressed onto the carrier).

Clean the Crown wheel carefully and warm to approximately 250 deg F (I use the oven, this is why you need to clean the gear, it will stink up the house if it still has any oil on it). Clean the Quaife unit and be ready to install the crown wheel quickly when you take it out of the oven. It helps to have a second pair of hands to install the gear because you have to get it on straight and get the bolt holes lined up. Start 4 of the bolts and make sure the gear is seated on the housing before it cools off and shrinks onto the Quaife housing. Remove the bolts and using RED Loctite install all bolts and torque to 61-66 ft/lbs.
Image

Press new bearings onto Quaife housing.

Remove the output shaft oil seals from the transaxle housings. With a torch or heat gun warm the area around the differential carrier outer bearing races (have some water available and when a drop just dances off the aluminum that should be warm enough) the outer race should come out of the housing easily now. There will be shims behind the bearing race in the bell housing side of the case remove them and set them aside. Install the new outer bearing race in the lower case (the one with all the gears still in it) and make sure it is seated in the housing. Now install the outer race in the bell housing side of the case without the shims but do not seat it in the housing. Leave it at least 0.100 inch away from the seat.
Image

Set the Quaife LSD with the crown wheel in the lower gear case and install the bell housing half. BE CAREFUL MAKE SURE NOT TO DAMAGE THE INPUT SHAFT SEAL AND MAKE SURE THE SHIFT SHAFTS SLIDE INTO THE POCKETS IN THE CASE. Secure it with the 19 bolts. Take the torch or heat gun and warm up the case around the output shaft area on the bell housing side. This will allow the bearing race to move in the housing.

Carefully remove the bell housing and measure the distance between the bearing race and the shoulder it is supposed to seat on. The shim you need is this dimension PLUS 0.006-0.010 inches this is the preload needed for the bearings. Measure the shim you removed from the case when you took it apart I have found at least 2 gearboxes that used the same shim as were installed at the factory. If you need to change the shim you can try a local Differential or transmission repair shop they often have a selection of shims and might have just what you need. Heat up the housing and remove the outer bearing race, install the shims and install the bearing. Install the output shaft seals.

Clean the mating surfaces of the gearbox case and use a light coat of Loctite 5203 sealant. Assemble the case and start all of the 19 bolts (I used blue Loctite) lightly snug 3-5 of the bolts and reinstall the dowel pins in the case. Using a cross pattern tighten the case bolts to 19-22ft/lbs.
Image

Re install the torque arm mounting bracket.

Install the gearbox and refill with oil. I recommend the original FORD transmission fluid but have also used Red Line MTL with good success.

This thread will be sticky'd until it is submitted into the Official How-To Archive.
 
#3 ·
I don't understand the purpose of heating various parts? I didn't bake my diff at 250F before crown installation, and I never used a heatgun to get the bearings and races to seat. I installed an OBX three months ago without heating anything up.

However, I can't stress enough to seal the trans mating surfaces well, because I didn't and it was leaking on the front side ever so slightly. Had to basically re-do the entire installation proceedure.

Use gasket remover on the mating surfaces of the trans case components. Use the gritty side of a sponge (no metal, no sandpaper, nothing abrasive) to remove whatever sealant there is. I used Loctite 7063 Cleaner.

I also wouldn't recommend Loctite 5203 as it isn't designed for aluminum mating, but metal to metal.

I used Loctite 5205 as it is specifically made for mating transmission components. It is much more heavy duty. I never used 5203, and it might be adeqate, but why take the chance I did and have to spend 10 hours fixing a problem that can be avoided. Use Loctite 5205.
 
#18 ·
I absolutely love the Torsen. It is the single best modification on my car. I didn't realize how awkward FWD cars with open diffs were until I drove with the Torsen.

As far as importance or priority goes, I'd rank installing an ATB differential second only to keeping your car mechanically sound. People should do it BEFORE adding power, but usually people take the same steps I did:

1. Add power
2. Ruin OEM clutch
3. Install ATB while installing new clutch.
 
#29 ·
I do a bit of driving on roads where I am able to appreciate the torsen... but my area is not very heavily populated. I agree that if you drive as you should in town, you won't notice the torsen (or use more than 150hp, much less need any kind of forced induction) very often. However, most people inquiring about the Torsen on here are performance-oriented, and an ATB diff is one of the most solid performance mods for any FWD car.

Where can you boost a car for ~$630, or even $1k?

I so strongly support the Torsen as an upgrade for anyone (especially anyone planning to add significant power) because I believe in planning things well... I think its a very good idea to be ready for the power you're going to add before you add it, instead of adding power first, then afterwords realizing that you forgot to do alot of peripheral things needed to support the power.
 
#30 ·
Where can you boost a car for ~$630, or even $1k?
A T2 is $700 or so shipped to your door. Unless you have tons of time and talent, you're gonna have to get that sucker installed. I had McNews do mine; I believe they took 6 hours to press things together and transplant the speed sensors. So the total is quite a bit over a $1k. And I say this despite this thread being about installing the LSD. I applaud people who can take it on, but the fact is, most people will have to pay to have the work done.

A cheap turbo solution should come in around $3k installed. I honestly believe most people on this board would get a kick out of the extra power more, despite many's insistence that the fun is in the twisties. Will the extra power wear down your clutch, engendering opening up the transmission? Yes? Will it happen the very day that you get to drive the turboed car? No.

I so strongly support the Torsen as an upgrade for anyone (especially anyone planning to add significant power) because I believe in planning things well... I think its a very good idea to be ready for the power you're going to add before you add it, instead of adding power first, then afterwords realizing that you forgot to do alot of peripheral things needed to support the power.
When I got my SVT upgraded, it cost me $11000 in parts, labor and tuning to get the power and all the supporting mods. Not everyone has that kind of money. I support them taking a risk with a smaller budget and trying to live with just the boost for as long as they can.
 
#32 ·
^^^Are those videos for the Getrag, or the MTX-75???
If MTX-75, please post it in the Zetec Performance Chat, and I'll delete this post in the SVT Performance Chat.
Thanks.